Control mechanism for sprinkler alarms



May 8, 1934.

C. P. HOWARD Filed April 18, 1932 CONTROL MECHANISM FOR SPRINKLER ALARMS 3 Sheets-Sheet l fo%c%ar/zzzzZ J6 CZz/fon P Ho we? Walk/ May 8, 1934. c, HOWARD 1,958,143

CONTROL MECHANISM FOR SPRINKLER ALARMS Filed April 18 1932 3 Sheets-Sheet 2 mufirw? CZzfron P195 m7? 3 MiG-n y! 7 Ma- M May 8, 1934. Q HOWARD 1,958,143

CONTROL MECHANISM FOR SPRINKLER ALARMS Filed April 18, 1932 3 Sheets-Sheet 3 2L as 154 f=4 a2 a; 66 a 20 52 1 50 v .fifi? 8L C'Zzffwz .PfiBww-E 84 5 adau ya' Patented May 8, 1934 UNITE STATES PATENT OFFICE CONTROL MECHANISM FOR SPRINKLER ALARMS Rockwocd Sprinkler Company of Massachusetts, Worcester, Mass., a corporation of Massachusetts Application April 18,

7 Claims.

This invention relates to sprinkler systems for fire protection purposes and particularly to mechanism for sounding an alarm when a sprinkler opens.

It is customary to provide a check valve in the supply pipe or" a sprinkler system and to provide alarm mechanism which will operate whenever the pressure below or on the supply side of the check valve substantially exceeds the pressure above or on the distribution side of the check valve. It frequently occurs, however, that the pressure above the check valve substantially exceeds the pressure below the check valve at the time when a sprinkler opens. In such cases, considerable time elapses after a sprinkler opens before the pressure falls sufiiciently below the supply pipe pressure to cause the alarm to be sounded.

It is the general object of my invention to provide improved control mechanism for a sprinkler alarm, so designed that it will operate on a pr determined rapid fall in pressure in the sprinkler system and above the check valve, and independent of the actual pressure in the sprinkler system or relative to the supply pipe pressure.

A further object is to provide means by which the operation of the alarm will be continued until interrupted as a result of manual closure of a shut-ofi valve.

My invention further relates to arrangements and combinations of parts which will be herein after described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawings, in which Fig. 1 is a side elevation, partly in section, of portions of a sprinkler system and alarm mechanism, having my improvements embodied there- Fig. 21s a sectional side elevation of my improved control mechanism;

Fig. 3 is a partial sectional plan view, taken along the line 33 in Fig. 2, and

Figs. 4 and 5 are sectional side elevations, similar to Fig. 2 but showing the parts in different positions.

Referring to the drawings, I have shown portions of a sprinkler system including a supply pipe 10, a check valve 11 and a distributing pipe 12, to which latter pipe the usual sprinklers and sprinkler pipes are connected. A branch pipe 14 is tapped into the casing 16 above the check valve 11 and is connected at its upper end to an outer or exhaust chamber 20 formed in a casing member 21.

1932, Serial No. 605,837

A second casing member 22 is mounted on the casing member 21 and contains an inner or pressure chamber 24. The lower end of the casing member 22 is partially closed by a partition 25 located between the chambers 20 and 24 and having an opening 26 at its center.

A diaphragm 30 divides the outer chamber 20 from the inner chamber 24 and supports a bypass device 32, extending through an opening in the center of the diaphragm and firmly secured therein by a binding nut 33. The upper portion of the device 32 is recessed to receive one end of a sleeve or bushing 35 having a pair of reversely disposed nozzle elements 36 mounted therein and provided with very small openings in their conical ips.

These nozzle members 36 are mounted in an axial passage 38 of the bushing 35, which passage at its inner end is connected through a branch passage 40 to the outer chamber 20. Consequently the inner chamber 24. is entirely closed at all times, except for the restricted openings through the nozzle members 36.

A pipe 42 is threaded into a recess 43 in the lower part of the casing member 21 and extends upward to a chamber 44 (Fig. 1) formed in a casing 45 below a diaphragm 46. The diaphragm is is provided with a plunger 47 adapted to engage a bell crank 48 when moved upward. On such engagement, the bell crank 48 closes a circuit between signal wires w and w and thus causes an alarm to sound.

The pipe 42 may also be provided with a branch connection 50 to the casing 51 of a water motor M by which a shaft 52 is rotated whenever water flows through the branch pipe 50 to an exhaust connection 53. Any suitable striker mechanism for a signal gong or other signal apparatus may be mounted on the shaft 52.

A valve port (Fig. 2) in a bushing 61 connects the outer chamber 20 to the recess 43 and is normally closed by a valve 62, mounted on a valve lever 63 which is pivoted at 64 in the casing 21. The valve 62 is normally yieldingly seated to close the port 60 by a spring 65.

The upper end 66 of the valve lever 63 is engaged by the lower face of the by-pass device 32 mounted at the center of the diaphragm 30 and is depressed on the occurrence of a preponderance of pressure above the diaphragm.

A latch 70 is pivoted at '71 in the casing 21 and is yieldingly moved by a spring '72 to the latching position shown in Fig. 4 whenever the end portion 66 of the lever 63 is depressed. The latch '70 also has a horizontally extending portion 77 positioned for engagement by the upper end of the stem 78 of a disc valve 80.

The disc valve normally rests on a valve seat 81 in a supplementary casing member 82, mounted in a recess in the lower part of the casing 21 and retained therein by a clamping nut 83. The port 84 below the valve 80 is connected by a branch pipe (Fig. 1) to the pipe 14 previously described. A shut-off valve 87 (Fig. 1) is inserted in the pipe 14 above the connection of the pipe 85 thereto.

A collapsible metal bellows or sylphon is mounted above the check valve 80 and surrounds the valve stem 78 thereof. A coil spring 92 within the sylphon normally presses the check valve 80 against its seat 81. The interior of the sylphon is freely connected to the chamber 20 and the exterior of the sylphon is exposed to the pressure in the casing 82 but there is no communication between the interior and the exterior of the sylphon.

Having described the details of construction of my improved control mechanism, the operation and advantages thereof are as follows:

Under normal conditions the parts assume the position shown in Fig. 2, with the pressures in the outer chamber 20 and the inner chamber 24 equalized through the restricted openings of the nozzle elements .36, and with a considerable volume of air or gas confined under sprinkler system pressurein the upper part of the chamber 24. The valves 62 and 80 are closed and the valve 87 (Fig. 1) is open.

Assuming now that one or more sprinklers are opened in the sprinkler system, the pressure in the distributing pipe 12 above the check valve 11 will drop more rapidly than the pressures in the chamber 20 and 24 can be equalized through the restricted openings in the nozzle elements 36. Consequently there will be a preponderance of pressure in the chamber24, which pressure will force the diaphragm 30 and by-pass device 32 downward against the lever 63, causing the lever to lift and open the valve 62 as the lever is moved to the position shown in Fig. 4, in which position the lever 63 will be retained by the latch 70.

The lifting of the valve 62 opens the passage 60 from the chamber 20 to the pipe 42 and consequently allows water in substantial volume and under sprinkler system pressure to flow through the pipe 42. This creates pressure in the chamber 44 (Fig. 1) and lifts the diaphragm 46, thus moving the bell crank 48 to close the signal switch and sound an alarm. Obviously, the switch may be arranged to open a closed circuit, if preferred. At the same time, water will flow through the pipe 50 to the water motor M, causing the motor gong to also sound an alarm.

As the valve 62 is locked in open position by the latch '70, the sounding of the alarm will continue until some person arrives and closes the shut-off valve 87 (Fig. 1). As soon as this valve is closed, the pressure in the outer chamber 20 drops, as this chamber is now shut ofi from the sprinkler system and is connected through the water motor M to the exhaust. Sprinkler system pressure is maintained, however, through the pipe 85 against the check valve 80 and the check valve is thereby raised.

As soon as the check valve is unseated, sprinkler system pressure obtains in the casing 82 and outside of the sylphon 90. The interior of the sylphon is connected to the exhaust at this time, so that the sylphon will be compressed, raising the valve rod 78 to engage the portion 77 of the latch 70 and thereby release the lever 63. Thereupon the valve 62 is closed by the spring 65, restoring all parts to initial position.

ter the fire is extinguished and normal water pressure has ben built up again in the sprinkler system, the shut-off valve 87 is opened, whereupon the pressures in the chambers 20 and 24 slowly equalize, compressing the air or gas in the upper part of the chamber 24. The apparatus is then in condition for further operation.

It will be evident that the sounding of an alarm depends simply upon the preponderance of pressure in the chamber 24 over the chamber 20, which occurs whenever there is a relatively rapid drop in pressure in the sprinkler system and in the outer chamber 20.

It will be further evident that the sounding of the alarm does not depend in any way upon the actual or relative pressure in the supply pipe below the check valve 11. Consequently it is not necessary to wait until the distributing pipe pressure drops below the supply pipe pressure in order to sound the alarm.

Furthermore, when the alarm has once started, the sounding of the alarm will be continuous until manually interrupted by the closing of the shutoff valve 87. Consequently the objectionable-intermittent action of the alarm sometimes previously encountered is avoided.

All parts of my improved mechanism are of simple and substantial construction and are extremely reliable in operation.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:-

1. In a sprinkler system having a main supply pipe and a check valve therein, control mechanism for a sprinkler alarm comprising a pressure chamber and a chamber forming part of an exhaust passage for said sprinkler system, 2. diaphragm separating said chambers, a device providing a much restricted opening between said chambers but permitting limited fiow between said chambers in both directions through said opening, a normally open connection from the exhaust chamber to the supply pipe above the check valve, which connection constitutes the sole connection of said control mechanism to the sprinkler system, a connection from said exhaust chamber through alarm-initiating mechanism to the atmosphere, a valve normally closing said latter connection, and means on said diaphragm effective to open said valve when said diaphragm is moved by a preponderance of pressure in said pressure chamber occasioned by a rapid drop in pressure in the sprinkler system, said valve when thus opened freely venting said sprinkler system through said exhaust chamber and valve to the atmosphere, and said restricted opening device being out of the path of venting fiow.

2. The combination in control mechanism as set forth in claim 1, in which means is provided for automatically securing said valve in open position after opening thereof, thereby effecting a continuous alarm.

3. The combination in control mechanism as set forth in claim 1, in which means is provided for automatically securing said valve in open position after opening thereof, thereby effecting a continuous alarm, and in which manually controlled means is provided for releasing said valve.

4. The combination in control mechanism as set forth in claim 1, in which means is provided for automatically securing said valve in open position after opening thereof, thereby efiecting a continuous alarm, and in which means is provided for automatically releasing said valve when said normally open connection is manually closed.

5. The combination in control mechanism as set forth in claim 1, in which the valve is mounted on a lever and in which a spring-pressed latch engages and locks said lever as soon as the lever has been moved to open the valve.

6. Control mechanism for a sprinkler system comprising a chamber having a normally open connection to the sprinkler system, a port for said chamber, a valve normally closing said port, pressure-operated means to move said valve to 

